April 20, 1893] 



NATURE 



i87 



capillary tube of I mm. bore is attached at right angles to the 

 main tube a little above the bend, ending in an open vessel. 

 The amount of mercury is so adjusted that there is a free 

 meniscus about tlie middle of the capillary tube. Any slight 

 increase in atmospheric pressure will then cause the main column 

 to rise, and the necessaiy mercury will be withdrawn from the 

 capillary. A faU of pressure will be indicated by a forward 

 movement of the meniscus in the horizontal tube. Thus the 

 rise and fall of the mercury in the main tube is exaggerated in 

 the ratio of the sec. ions of the tubes, in this case 400 : i. Hence 

 it is possible to observe a variation of :i^ij mm. Should the 

 variation of the pressure be so large as to drive the meniscus 

 out of the tube altogether, it can be brought back by screwing 

 the steel cylinder up or down. In spite of the errors introduced 

 by variations of temperature and the faults due to capillary 

 adhesion, variation of sectionjl area of the tube, and impuri- 

 ties in the mercury and the gla.s, the instrument appears to be 

 well adapted to the observation of small fluctuations of pressure, 

 such as the diurnal variation and the small and rapid oscilla- 

 tions peculiar to windy days. On one such occasion an ampli- 

 tude of two cvr three centimetres was obtained in the course of 

 two hours, during which an ordinary barometer remained per- 

 fectly steady, and a Richard barograph showed only a faintly 

 waved line. 



If we may accept literally Sir Edward Braddon's glowing 

 descriptions of gardens in Tasmania, that island ought to be 

 the paradise of horticulturists. Speaking the other day before 

 the Indian section of the Society of Arts, he said of the garden 

 he birosell cultivated there for ten years : "All the year through 

 that garden had its charms of colour and perfume to lavish upon 

 me; always there were life and growth in progress, and new 

 delights unfolding themselves out of nature's bounteous lap.'' 

 His monster pelargoniums, that stood from 3 to 4^ feet high, 

 and had a circumference of 9 to 27 feet, were sources of increas- 

 ing pride and pleasure to him, as they were of successive glories 

 of flower. As for his fruit trees and vegetable garden, they 

 yielded a never-failing supply of food for the table that in Eng- 

 land, purchased of the greengrocer, would have cost about;^ioo 

 a year. "Many another garden like unto mine is there," said 

 Sir Edward, "in Tasmania and New Zealand, gardens in which 

 all ibe fruits and flowers of the temperate zone flourish abun- 

 dantly, and in which it is possible for a European to work all 

 iheyeariound without fear of sunstroke or frostbite." These 

 panegyrics were uttered in the course of an address in which 

 the spe.iker tried to persuade Anglo-Indians that after their 

 term of service in the East they would find it pleasanler and 

 more profitable to settle somewhere in Australasia than to re- 

 turn to England. The address is an interesting one, and may 

 be read — with the discussion to which it gave rise — in the 

 current number of the Journal of the Society of Arts. 



The Hornsey Local Board, Hi^jhgate, has set a good example 

 to other Local B jards by organising an excellent museum of 

 modern sanitary appliances. About tv\'o years ago it occurred to 

 the Board that it might be well to bring together some speci- 

 mens of the most improved fittings for the guidance of builders 

 and others. Accordingly a suitable room was erected, and 

 manufacturers were invited to send examples of their manu- 

 lactures. In order to ensure the permanence of the museum 

 k was stipulated that all articles deposited should become the pro- 

 perty of the Board ; and thus an important collection— which 

 BOW occupies seven rooms — has been gradually formed. It is 

 open free to ibo public on week days, and a good catalogue of 

 the contents of the museum has just been issued. 



Mr. Robert Service, of Maxwelltown, writing in the 

 new number of The Annals of Scottish Natural History, says 

 it is somewhat surprising, considering the untold myriads of 

 NO. 1 525. vol.. 47] 



voles that have overrun the sheep pastures in southern Scotl.md 

 for a year or two past, that so few variations in colour have 

 been reported. He himself has not seen any noteworthy aber 

 ration among those he has observed in peregrinating through 

 their haunts, but the shepherds have reported an occasional pied 

 example. Mr. Service has, however, a very strong impression 

 that the "hill voles" are decidedly of a more siioky tint than 

 those to be found in the lower lands among the hedges and 

 plantations. The latter seem to develop a much ruddier colour 

 on the fur along the back, and the general tone of gray seems 

 much brighter than that of the voles that have ravnged the 

 upland pastures. 



Mr. Thomas Steel continues in the Victorian NataraliJ 

 for February his remarks on some zoological gardens he has 

 visited. The collection at Rundwick Park, Sydney, contains 

 some very fair specimens of various kinds, especially among 

 the large carnivora and the monkeys ; but he thinks a visitor 

 from abroad would be disappointed in the small number of in- 

 digenous animals. Melbourne and Adelaide seem to be better 

 ofi" in this respect. Of the Melbourne Gardens, as compared 

 with those he has visited elsewhere, he has a high opinion. 

 Nowhere has he seen more attention given to the rational 

 housing and to the comfort of the animals. 



Opponents of the doctrine of evolution have often tried to 

 support their view of the subject by reference to the supposed 

 sudden appearance of metaspermic plants in the rocks of the 

 Cretaceous period. In the American A^aturalist for April Mr. 

 Conway McMillan deals with this point in an article on "the 

 probable physiognomy of the Cretaceous plant population." 

 He undertakes to show, first, that the appearance of Cretaceous 

 metaspermic plants is proved, by the fossils, not to have been 

 sudden, but gradual, and consequently, in Cretaceous time, the 

 general preponderance of plant-population was strongly conifer- 

 ous, fern and cycadean ; and second, that the conditions of 

 Cretaceous time were such that the new and scattered meta- 

 .spermic plants were placed under circumstances similar to those 

 in which to-day variation is most rapid and plasticity is greatest 

 for each species and even for every individual. 



Some interesting notes on alligator shooting in Trinidad 

 are contributed by Mr. S. Devenish to the February number of 

 the Trini iad Field Naturalist' s Club Magazine. In Trinidad it is 

 commonly believed that if any one attempts to touch an alliga- 

 tor's nest, he runs great risk of being attacked by the mother 

 alligator, who is always on the watch to defend her progeny. 

 While surveying on the left bank of the Caroni, Mr. Djvenish 

 came once upon one of these curious constructions, and so 

 frightened were his eight men at his goin^j to examine and de- 

 molish it, that they all ran away to a distance of at least twenty 

 yards, warning him of the danger of the " Maman Caiman," 

 which was sure to attack him. However, having beside his 

 bowie knife at his side, his cutlass in hand, he prepared for de- 

 fence, and quietly demolis'.ied with perfect immunity the large 

 ne.t, in which he found a number of eggs. Of these a few 

 were blown for his collection, and the rest left to hatch near a 

 little fountain in his garden. After a few days the hatching 

 took place, and it was as curious as interesting, says Mr. Deven- 

 ish, "to see the little alligators, still adhering to the shells by 

 their umbilical cords, bri>kly showing fight when approached, 

 dragging the shell behind them and rushing with o])en j.iws at 

 anything presented to them and madly biting it." 



The Royal Dublin Society has published in its Proceedings 

 a list of some of the Rotifera of Ireland, by Mis? L. S. 

 Glascott. The list is the result of research carried on from 

 May to October in 1891. The number of rare and new species 

 obtained during this short period seems to indicate that the 



